1. Field of the Invention
The invention relates to downhole tools for an oil well. More particularly, the invention relates to performance enhancing devices for inflatable packers.
2. Prior Art
Inflatable packing elements have been used in the downhole environment for an extended number of years for many different sealing operations and other operations. Such packers have been very useful for their intended purposes and are generally reliable to provide a positive seal when inflated. One of the drawbacks of inflatable tools is that they inflate as one unit unless specific actions have been taken to prevent that. One prior art means to create inflation control is to differentially cure the rubber from one end of the inflatable device to the other. Since differential curing is difficult and expensive, it is not preferred. Another means of creating a progressively inflatable packer is to stagger competitive layers of rubber in the construction of the inflatable element. In this type of construction, one end of the packer has relatively few layers of rubber where the other end of the packer will have a relatively large number of layers of rubber. Thus, fluid pressure provided to the inflatable element will expand the areas having relatively fewer layers of rubber first and expand areas having a relatively larger number of layers second.
Although these devices do exist the art is in need of alternative methods for controlling inflation of an inflatable element.
The invention provides an alternative construction for controlling the inflation of an inflatable element by selectively allowing certain areas of the element to inflate prior to other areas of the element. This is accomplished through the employment of a non-oriented continuous strand mat, preferably of fiberglass although other fibers may also be used, such as carbon fiber, aramid fiber, etc. The mat is embedded in the inflatable material with more fiber being added in areas where additional resistance to inflation is desired and less fiber being added to areas where less resistance to inflation is desired. By carefully regulating the addition of fiber to the inflatable material one can create an inflatable element that will inflate only in selected areas first followed by other selected areas second and so on until all areas of the inflatable element have inflated.